<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Document</title>
</head>
<body>
	<!-- oninput事件在用户输入时触发，当元素值发生变化时立即触发 -->
	序号：<input type="text" id='xh' oninput='myFunction()'>
	列号：<input type="text" id='lh'>
	<script>
		function myFunction(){
			document.getElementById('lh').value=document.getElementById('xh').value;
		}
	</script>
</body>
</html>